The brazen operation was noticed this week in Lake Innaren near Växjö in southern Sweden when the lake's six official fishing supervisors stumbled on 180 unauthorized crayfish cages.
Each cage contained around ten of the little crustaceans.
“We suspect that there's a commercial purpose behind this. It is well planned and well executed,” Thomas Spjuth told public broadcaster SVT on Wednesday.
It comes just days before crayfish season kicks off, which involves attending special parties ('kräftskiva') eating the juicy beasts while washing them down with snaps and some very loud drinking songs.
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Swedes enjoying a crayfish party. Photo: Carolina Romare/imagebank.sweden.se
Crayfish has been popular in Sweden for centuries and became an annual tradition because it used to be a delicacy that could only legally be fished in late summer.
These days you can buy imported crayfish year-round, but the domestic variety is still high in demand, which has led to several poaching incidents in the past.
Last year police caught two fishy criminals in the act at Lake Vättern, Sweden's second biggest lake, where they were busy stealing crayfish worth between 20,000 and 30,000 kronor.
For Lake Innaren, it is the second year in a row it has been hit by poachers, so although Spjuth and the rest of the team have not managed to catch the criminals, they remain vigilant.
“We're out and about on the lake and on shore, day and night. We investigate who is moving around in the area and check if, for example, they have a valid fishing licence,” he told SVT.
The crayfish caught in the illicit cages will be released back into the lake, he said.